Trophic network models explain instability of Early Triassic terrestrial communities.

Studies of the end-Permian mass extinction have emphasized potential abiotic causes and their direct biotic effects. Less attention has been devoted to secondary extinctions resulting from ecological crises and the effect of community structure on such extinctions. Here we use a trophic network model that combines topological and dynamic approaches to simulate disruptions of primary productivity in palaeocommunities.

Comment on "Statistical independence of escalatory ecological trends in Phanerozoic marine invertebrates".

The analysis of Madin et al. (Reports, 12 May 2006, p. 897) of Phanerozoic diversity failed to support expected correlations between carnivores and noncarnivores, leading the authors to reject escalation as an important macroevolutionary process.